编译无法通过。为什么？

zhangzhm

1. 
   
2. /* hello.c */
   
3. /* The necessary header files */
   
4. /* Standard in kernel modules */
   
5. #include <linux/kernel.h>; /* We're doing kernel work */
   
6. #include <linux/module.h>; /* Specifically, a module */
   
7. /* Initialize the module */
   
8. int init_module()
   
9. {
   
10. printk("Hello, world - this is the kernel speaking\n");
    
11. /* If we return a non zero value, it means that init_module failed and
    
12. * the kernel module can't be loaded */
    
13. return 0;
    
14. }
    
15. /* Cleanup - undid whatever init_module did */
    
16. void cleanup_module()
    
17. {
    
18. printk("Short is the life of a kernel module\n");
    
19. }
    

复制代码

[root@RedHat zhangzhm]# gcc -O6 -Wall -DCONFIG_KERNELD -DMODULE -D__KERNEL__ -DL
hello.c: In function `init_module':
hello.c:9: warning: implicit declaration of function `printf'
hello.c: In function `cleanup_module':
hello.c:17: warning: implicit declaration of function `printk'

编译无法通过。为什么？